Edward Schernau wrote:
>
> Chris Mauritz wrote:
>
> > > Ive done some superficial performance tests using dd, 55MB/s write
> > > 12MB/s read, interestingly i did get 42MB/s write using just a 2 way ide
> > > raid0, and got 55MB/s write with one drive per channel on four channels
> > > (i had no problem writing, just reading) so surprisingly i dont think
> > > the drive interface is my bottleneck.
> >
> > I find those numbers rather hard to believe. I've not yet heard of a
> > disk (IDE or SCSI) that can reliably dump 22mb/sec which is what your
> > 2 drive setup implies. Something isn't right.
>
> Check http://www.tomshardware.com , they review the Promise IDE RAID
> card
> (the hacked one for $30). They get some pretty insane throughputs
> on some ATA66 drives.
>
Gee, they look pretty awesome, excellent performance.
The only drawback i can think of is that it wouldnt be as flexible as
software raid.
> > RAID0 seemed to scale rather linearly. I don't think there would be
> > much of a problem getting over 100mbits/sec on an array of 8-10 ultra2
>
> I tested a 3 drive RAID0 set where 1 disk = 1.7 M/sec, 2 disks = 3.4
> M/sec,
> but 3 disks only = 3.9 M/sec. These were 5 M/sec disks on a AHA2940.
> I think SCSI bus overhead and contention issues play an important role.
>
> Ed
I also see linear performance increas with two drives, but after that it
tails off.
Glenn
